Crawler



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CRAWLER Filed Dec. 27, 1927 2 Sheets-Sheet l ZKM Y* irma/ve Y C. H. RUTH March 3, 1931.

CRAWLER Filed Dec.

27, 1927 2 Sheets-Sheet 2 Patented Mar. 3, 1931 UNITED STATES PATENT OFFICE CHARLES H. RUTH, OF WALNUT PARK, CALIFORNIA, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO RUTH DREDGER MANUFACTURING CORPORATION, LTD., OF LOS AN- GELES, CALIFORNIA, A CORPORATION CRAWLER Application led December 27, 1927. Serial No. 242,790.

This invention relates to a crawler, such as may be used for imparting mobility to a vehicle, carrying heavy machinery, for example, steam shovels, ditchers, guns, arin tractors or the like.

Such crawlers utilize usually a sprocket chain drive, which extends around several idler wheels and which has a lower, substantially horizontal reach. This chain carries transverse tracks that engage or grip the ground at the horizontal reach. Such arrangements are now well-known, and require no further description.

It is one of the objects of my invention to improve in general this type of tractor or crawler.

It is another object of my invention to provide a. drive for the tracks that is better adapted to maintain a positive connection with the chain or belt.

It is still another obj ect of my invention to make it possible to keep the links of the chain free from foreign matter, such as dirt or stones, and thereby to prevent clogging of the driving mechanism.

My invention possesses many other advantages, and has other objects which may be made more easily apparent from a consideration of one embodiment of my invention. For this purpose I have shown a form in the drawings accompanying and forming part of the present specification. I shall now proceed to describe this form in detail, which illustrates the general principles of my invention; but it is to be understood that this detailed description isnot to be taken in a limiting sense, since the scope of my invention is best defined by the appended claims.

Referring to the drawings:

Figure 1 is a side elevation of a crawler embodyino' my invention, with one side frame removed;

Fig. 2 is a top plan View thereof;

Fig. 3 is a sectional view, taken along plane 3-3 of Fig. 1, but omitting the representation of the track elements in planes back of the section plane 3 3; and

Fig. 4 is an isometric view of one of the tracks.

In the present instance, the crawler structure is shown as `mounted between two structural beams 11 and 12. A pair of end idlers 13 and 14 at each side of the crawler is used to guide the track elements 15 in a belt-like configuration. Further idlers such as 16 and 17 are also provided that engage only the lower reach and serve to hold that reach in contact with the ground.

`These idlers are mounted on shafts 18, 19, 20, and 21 that are supported in appropriate bosses in the beams 11 and 12. The active faces of all of the idler-s are wedge shaped to fit between the offset projections 22, 23, and 24, 25 formed on the inside of the tracks 15. These tracks 15 are pivotally jointed together to form a wide belt. For his purpose, they are provided, as shown most clearly in Fig. 4, with apertured bosses on each side; these bosses are numbered 26, 27, 28, 29, 30, 3l and 32 at one side; and 33, 34, 35, 3G, and 37 at the opposite side. Boss 29 of one track is adjacent a boss of the adjacent track; bosses 26 and 27 accommodate between them, the boss 33 of the adjacent track; bosses 27 and 28 similarly accommodate boss 34 of the adjacent track; bosses 30 and 31 similarly accommodate boss 36, and bosses 3l and 32 similarly accommodate boss 37. Thus an articulated belt structure is provided, by passing shafts such as 38 through the series of alined bosses, 4as clearly indicated in Fig. 2. These shafts can be held in place against axial movement as by pins passing through Vthe shafts and into apertures 39 provided in the upstanding ribs 401 adjacent bosses 26 and 32.

Rollers 40 are mounted on shafts 3S between bosses 33 and 27, and between bosses 37 and 31. These rollers are intended to be engaged by a driving sprocket to drive the articulated belt, in a manner to be hereinafter described.

Rollers intermediate those accommodated on shafts 33 are also provided on the short stub shafts 41 held in bosses 42 on the track 15. In this way, the number of rollers 40 is increased, and the pitch between roller centers is reduced to half. This is important, because it makes it possible to use driving pinions 43 having smaller pitch between teeth.

These pinions are keyed to a transverse shaft 44 driven through a train of gearing 45 (Fig. 2), and engage the upper reach of the track structure.

The choice of drive wherebyV the upper reach is engaged by these driving pinionsis advantageous,l for it permits the use `of idler pulleys 46 to urge the belt downwardly into engagement withy Vthe driving sprockets.

These wheels can -be mounted on atransverse shaft 47 journalled in the pillow blocks 48 on the frame structure 11-12. d

In the course of operation of the crawler, dirt on stones or the like isvapt to be carried up by the belt and it may interfere with the idlers 46. In order'to prevent this, and to keep the upper part ofthe b'elt'clean, I provide Scrapers 49 oneach sidefof each idler 46. These Scrapers can be'made Yfrom'flat material fastened in'kany appropriate manner to a Stationary part of the structure,such as to the inner surfaces of the blocks y48.

These Scrapers are preferably slanteddown# wardly and outwardly so as to serve asbaffles, whereby dirt or stones are deflected away from the pulleys 46. AS shown most clearly in Fig. 2, thebaliles or guards 49 are joined by a crossbar 50 to lend rigidity thereto.

I claim:

1. In a crawler, a jointed track Structure forming an upper and a `lower reach, a driving wheel beneath the upper reach and engaging it, and a guard above the upper reach and adjacent the wheel for keeping foreign matter from the structure above the driving wheels.

2. In a crawler, a Stationaryframe having two spaced side members, a flexible 'track structure between the side members, apairl of driving wheels beneath the upper reach of the structure and at-opposite sides thereof, a pair of idlers, respectively opposite the driving wheels and on the other Side of the Structure, and ay guard for each idler, Said 'guard 5 being in the form of a U-Shaped Strap einbracing the idler and having its legs attached to the adjacent side of the Stationary-frame.

In testimony whereof I havefhereunto Setl my llilLIlCl.

` f CHARLES H. RUTH. 

